title: Immunoglobulin expression in human lymphoblastoid cell lines with early B cell features.
abstract: Immunoglobulin expression was studied by direct immunofluorescence and by biosynthesis experiments in two human cell lines Raji and T 5.1. The basic phenotype of these cells was close to that of pre-B cells: large cells with intracytoplasmic IgM with a predominance of mu chains over light chains and no detectable surface immunoglobulins. The apparent molecular weight of heavy and light chains was abnormally large. Immunoglobulins were secreted at a low rate as pentameric IgM in the T 5.1 line and as subunits and free light chains in the Raji line. Spontaneous variations of this phenotype were observed: the cultured cells acquired mu and lambda chains, then additionally delta chains while they progressively lost detectable cytoplasmic mu chains, thus leading to a mature B cell phenotype. Subsequently, the cells had no detectable surface and cytoplasmic immunoglobulins and then they displayed a pre-B cell phenotype again. Attempts to induce further maturation using various potential inducers were unsuccessful.
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology*; D002460:Cell Line; D004591:Electrophoresis, Polyacrylamide Gel; D005455:Fluorescent Antibody Technique; D006801:Humans; D007075:Immunoglobulin M / Q000032:analysis; D007142:Immunoglobulin gamma-Chains / Q000032:analysis; D007146:Immunoglobulin lambda-Chains / Q000032:analysis; D007136:Immunoglobulins / Q000032:analysis* / Q000096:biosynthesis; D008213:Lymphocyte Activation; D010641:Phenotype; D011947:Receptors, Antigen, B-Cell / Q000032:analysis
chemical_list: D007075:Immunoglobulin M; D007142:Immunoglobulin gamma-Chains; D007146:Immunoglobulin lambda-Chains; D007136:Immunoglobulins; D011947:Receptors, Antigen, B-Cell